Whether a landlord can or cannot raise a tenant's rent and how much that rent goes up by depends on whether or not the rental agreement is a lease and how soon the rent goes up after the tenant has been served written notification. Additionally, rent may not be increased in retaliation for a legal right exercised by the tenant who may have upset the landlord personally, and rent may not be increased on a discriminatory basis, says Nolo.
If a rental agreement is a lease, the rent may not legally be raised for the entire term of the lease. However, it may be a good idea to have a lease rewritten midterm rather than confronting the landlord on the issue if the tenant has also made breaches of the lease agreement recently, such as making late payments, warns Nolo.
If a tenant has a periodic rental agreement where he pays by the month with no lease, the landlord must give notification at least 30 days before the increase in most states. Most states also require this notification to be made in writing to be legally binding. In a lease, the rent may be changed between the leasing periods, where the landlord and tenant may discuss the conditions of the new contract if there are issues. It is up to the landlord's discretion if forward notification is given for an intent to raise rent in the case of a lease agreement, says Nolo.
A tenant may have a legal case for discrimination or retaliation if witnesses can confirm the discriminatory behavior, or if the tenant can prove a connection between the rent increase and, for instance, a complaint made to a public agency about the tenant's housing unit, says Nolo.